Re:Let's build a circuit that displays an image on a VGA mon...
by exar0815 on Sunday July 07, 2019 @01:39PM
(#20376393)
I can only recommend the "Veronica"-Series of Quinn Dunki, where she builds a complete graphics card for her 8-Bit-computer, as well as the computer itself
Re:Let's build a circuit that displays an image on a VGA mon...
by jaak on Sunday July 07, 2019 @03:19PM
(#20377157)
Not to take away from Quinn Dunki's accomplishments, one big difference is the Veronica used an ATmega 324PA - basically an 8 bit 20 MIPS RISC CPU.
Generating a VGA signal is trivial for this powerful chip. Entire retro game consoles have been built with similar ATmega chips alone
Ben Eater is building a VGA card from discrete components, a somewhat more difficult task. The first part covers building the H/V timing sync circuit (no programmable clock source here!). It's worth taking a look if you're into this kind of thing.
Re:Let's build a circuit that displays an image on a VGA mon...
by dotancohen on Monday July 08, 2019 @02:11AM
(#20380274)
Even more amazing, after watching Ben's video, I was thinking too myself "That wasn't so hard". Other than a few Arduino projects I've never used an IC, but I was able to follow along with Ben completely.
In fact, I think that a tutorial dedicated just to explain the VGA standard, the same length as Ben's tutorial, would have been less clear and informative.
Re:Let's build a circuit that displays an image on a VGA mon...
by mrob on Sunday July 07, 2019 @06:40PM
(#20378449)
Although NAND gates are universal gates (any combinatorial boolean logic function can be built from nothing but NAND gates), in practice it's usually more space efficient to use a mixture of different gates.
Re:Let's build a circuit that displays an image on a VGA mon...
by deaddodo on Sunday July 07, 2019 @07:52PM
(#20378816)
To be fair, it's almost impossible to build anything out of fully discrete components these days. If you use a TO series transistor, you could argue those are also ICs and vacuum tubes/relays aren't cheap or too easily accessible.
Re:Let's build a circuit that displays an image on a VGA mon...
by mrob on Sunday July 07, 2019 @08:59PM
(#20379107)
Chip photography site zeptobars.com has some photographs of modern transistors, and while some have interesting geometry, I didn't see anything that I'd consider an integrated circuit, i.e. something that would be drawn as more than a single transistor symbol on a schematic.
There are some "discrete" transistors with built-in ESD protection, e.g. NCV8440A, but those are unusual, and under normal operating conditions they work just like a normal transistor so I'd still count them as discrete components.
Re:Let's build a circuit that displays an image on a VGA mon...
by lopmotr on Sunday July 07, 2019 @08:56PM
(#20379089)
Transistors in individual packages are called discrete components. Even if they use the same technology as ICs, they're still discrete. You can certainly build useful analog and power circuits with only discrete components. Somebody even made a CPU from them [1] which was a much bigger circuit than TFA's IC video card will be so it's worth distinguishing truly discrete from simple ICs.
Re:Let's build a circuit that displays an image on a VGA mon...
by Lowkeyloki on Sunday July 07, 2019 @04:07PM
(#20377477)
Depending on the definition of the word "image" in this context, I'd love to see people play the electronics component version of code golf to see what the fewest number of basic components would be required to put an "image" on a screen. No SOACs allowed.
Re:Let's build a circuit that displays an image on a VGA mon...
by rasz on Sunday July 07, 2019 @05:12PM
(#20377887)
You can get this to display "image" by just adding one wire between clock source and one/all of VGA analog inputs. It will be a random checkerboard, but still an image.
Re:Let's build a circuit that displays an image on a VGA mon...
by abdullahkhalids on Monday July 08, 2019 @04:44PM
(#20386577)
He meant to say that each pixel will be randomly black or white. What will really happen is that the color choice for each pixel will not be random, but can actually be predicted by the various clock frequencies he used.
Re:Let's build a circuit that displays an image on a VGA mon...
by atum47 on Sunday July 07, 2019 @09:24PM
(#20379227)
I've been following ben eater for about 2 years now. I've learned so much from his well explained well illustrated videos. Right now it's kinda hard for me to get my hands on every component he uses, but soon I'll take a shot at building a 8 bit computer as well. I'll may start with a full adder built with transistors only.
Re:Let's build a circuit that displays an image on a VGA mon...
by lnsru on Monday July 08, 2019 @02:42AM
(#20380413)
Hi, I don’t know your background, but why are you not building your 8 bit computer in FPGA? There are many nice cheap boards like MAX1000 from Arrow or Lattice. It’s really cool learning project! Transistor only design will have many problems: transistors are bigger than you think and small ones in VML0806 package are almost impossible to solder by hand.
Re:Let's build a circuit that displays an image on a VGA mon...
by atum47 on Tuesday July 09, 2019 @06:04PM
(#20397137)
I'm a software engineer undergrad, I do most high level stuff. I took digital circuits on college, cause I like electronics. One day watching videos on YouTube I saw ben eater project and loved it. I thinker with Arduino and Raspberry pi, but never built anything cool like that. I just want to give it a try, I guess
Re:Let's build a circuit that displays an image on a VGA mon...
by dreamcompiler on Sunday July 07, 2019 @09:30PM
(#20379247)
That's gonna take a lot of transistors. I suggest doing it with gates instead. Using transistors is like programming a computer with machine language; using gates is more like a good macro assembler.
Building yourself one NAND gate with transistors and resistors would be a valuable learning experience, but building 100 of them won't teach you anything new.
Re:Let's build a circuit that displays an image on a VGA mon...
by eatonphil on Monday July 08, 2019 @08:41AM
(#20382200)
Yes that's hard to debate. But if you want to get the experience without the physical complexity you can always build an 8-bit computer in a simulator like they do in many college courses. I used Logisim [0] at college for this following the Harris and Harris [1] textbook and it was a straightforward experience.
Re:Let's build a circuit that displays an image on a VGA mon...
by tyingq on Sunday July 07, 2019 @07:11PM
(#20378619)
Somewhat related, here's a video card for a MAC SE done with a BeagleBone and it's microcontroller like PRU secondary processors: https://trmm.net/Mac-SE_video
http://quinndunki.com/blondihacks/?page_id=1761
Generating a VGA signal is trivial for this powerful chip. Entire retro game consoles have been built with similar ATmega chips alone
Ben Eater is building a VGA card from discrete components, a somewhat more difficult task. The first part covers building the H/V timing sync circuit (no programmable clock source here!). It's worth taking a look if you're into this kind of thing.
In fact, I think that a tutorial dedicated just to explain the VGA standard, the same length as Ben's tutorial, would have been less clear and informative.
For comparison, a slightly less powerful microcontroller can do this:
https://www.linusakesson.net/scene/craft/
From 7400 series devices, which are very simple integrated circuits by modern standards, but still integrated circuits.
So it's clear, a 74xx is just a bunch of NAND gates. Nothing at all higher level than that.
https://easyeda.com/normal/74161X2-4qkCwOIZh.png
https://zeptobars.com/en/read/NXP-PMST3904-NPN-BJT
https://zeptobars.com/en/read/NXP-MMBT3904-npn-bjt
https://zeptobars.com/en/read/NXP-2N7002-TrenchMOS-N-Channel...
There are some "discrete" transistors with built-in ESD protection, e.g. NCV8440A, but those are unusual, and under normal operating conditions they work just like a normal transistor so I'd still count them as discrete components.
[1] https://monster6502.com/
Making it seem easy != easy
That you can do with a single LED.
Or do you mean the top left square is randomly black/white?
Building yourself one NAND gate with transistors and resistors would be a valuable learning experience, but building 100 of them won't teach you anything new.
[0] http://www.cburch.com/logisim/
[1] https://www.goodreads.com/author/show/13816512.David_Money_H...
Should be the very first video any would-be VGA card designer views... (I want to design one in the future...)